1. Field of the Invention
This invention relates to a mixer capable of mixing and dispensing relatively small quantities of cement and concrete in a continuous manner. As such it is generally applicable to the many fields of construction that utilize concrete. More generally the invention could find use in any field requiring the mixing of one or more aggregate or powdered solids with a fluid to produce a slurry or mixed composite in a continuous manner.
It should be noted that although a principal application of the invention is to mixing concrete, cement, and mortar, the principles embodied herein are suitable for mixing any type of powdered or granular solid with a liquid. Examples include preparing batter, ceramic mixes such as slip, plaster, and paint; mixing resins and curing or hardening agents; and conditioning soil, as for planting. These are but several examples of possible applications.
Thus it can be seen that the potential fields of use for this invention are myriad and the particular preferred embodiment described herein is in no way meant to limit the use of the invention to the particular field chosen for exposition of the details of the invention.
A comprehensive listing of all the possible fields to which this invention may be applied is limited only by the imagination and is therefore not provided herein. Some of the more obvious applications are mentioned herein in the interest of providing a full and complete disclosure of the unique properties of this previously unknown general purpose article of manufacture. It is to be understood from the outset that the scope of this invention is not limited to these fields or to the specific examples of potential uses presented hereinafter.
2. Description of the Prior Art
Mixers for preparing mixes of solids in powdered or aggregate form and a liquid are old. Such mixers are typically employed to prepare batter and dough for baking, concrete and cement for building, resins for manufacturing, and similar mixtures wherein two or more raw materials are blended to prepare a homogeneous material for ultimate use. Mixers generally include a receptacle to hold the mixture, a beater or agitator to blend the constituent materials, and a chute or analogous structure for dispensing the final mixture.
U.S. Pat. No. 4,566,799, issued to Yasuro Ito et al. on Jan. 28, 1986, describes a power driven agitator and a power driven feeder. Fine aggregate and coarse aggregate are fed into the mixing chamber by a belt conveyor, rather than by augers, as provided in the present invention. Also, materials are delivered into a trough open at the top at plural points along the trough in Ito et al. By contrast, in the present invention, all solids are introduced at a single feed point. In the present invention, a housing corresponding to the trough of Ito et al. is enclosed, although split for ready access to the interior thereof. The device of Ito et al. lacks the drive and single motor of the present invention.
U.S. Pat. No. 1,753,716, issued to Jack M. Owen on Apr. 8, 1930, describes a mixer for dry cement comprising a mixing chamber supplied by a hopper at one end and having a delivery chute at the other end. The mixing chamber has an auger formed in two sections. The first section has a full helical screw for propelling constituent materials towards the second section, where paddles blend or mix the constituents. By contrast, the present invention provides three sections, the last being an auxiliary propelling section. Owen also lacks the drive system of the present invention.
U.S. Pat. No. 3,469,824, issued to Robert C. Futty et al. on Sep. 30, 1969, describes a mixer having a single auger. The blade is different from that of the present invention. Also, there is no separate feed auger for introducing constituent materials into the mixer. Hence, the drive arrangement necessarily differs from that of the present invention.
U.S. Pat. No. 4,298,288, issued to Alvin J. Weisbrod on Nov. 3, 1981, describes a wheeled, mobile mixing apparatus having a compound mixing chamber, rather than the single, linear chamber of the present invention. This arrangement lacks the auger having blades of different character, as found in the present invention. Constituent solids are introduced at several inlet ports into the mixing chamber in Weisbrod, rather than at the single inlet of the present invention. Weisbrod employs many motors to accomplish his various functions, whereas the present invention has but one motor.
U.S. Pat. No. 5,213,414, issued to Bennet M. Richard et al. on May 25, 1993, describes a mixer having a single, linear mixing chamber. However, unlike the present invention, Richard et al. provides a a mixing auger lacking a blade exhibiting different types, as seen in the present invention. Also, Richard et al. provide a feed auger having a dedicated motor.
U.S. Pat. No. 4,223,996, issued to Paul Mathis et al. on Sep. 23, 1980, describes a mixer having a single feed auger which urges mix material into a mixing chamber and then to a discharge port. The inlet chamber of Mathis et al. is of variable diameter, and small quantities of cement mix or sand could become trapped, and removed only upon cleaning the mixer. By contrast, the mixing chamber of the instant invention has a constant diameter, which avoids entrapping small quantities of mixed material.
German Patent Document No. 31 42-053 A1, by Wachter et al., dated May, 1985, describes a similar mixer with abruptly changing chamber diameters. By contrast, the mixing chamber of the instant invention has a constant diameter for promoting undisturbed migration of mixed material and for ease of cleaning.
A mixer comprising paddles mounted on a rotating shaft is seen in U.S. Pat. No. 2,298,258, issued to William J. Ziler on Oct. 6, 1942. This mixing apparatus is located in a chamber dedicated exclusively to mixing, and action of the paddles pushes the mixed product towards another chamber. The mix is drawn from this second chamber for dispensing through a pipe.
Another arrangement wherein paddles agitate the constituent ingredients into a homogeneous, blended mix is seen in U.S. Pat No. 2,276,237, issued to Ronald P. Lowry on Mar. 10, 1942. In Lowry's device, dry, powdered cement is gravity fed from a hopper into a conveyor including a screw auger, and propelled towards a vertical conduit. Water is arranged to be introduced to the dry mix in a conduit forming an annulus surrounding the vertical conduit. Water is metered in Lowry's device by a metering pump which is driven by fixed connection to the screw auger shaft.
The dry mix and water are discharged into a mixing chamber having paddles fixed to a rotating shaft. The dry and wet constituents are mixed as they migrate toward the end of this mixing chamber. The final, prepared mix is discharged through an opening formed in the floor of the mixing chamber at the end thereof, and held in a storage tank. As in the case of Ziler, a pipe draws the mix from this storage tank for dispensation and use.
U.S. Pat. No. 2,296,505, issued to Kent B. Diehl on Sep. 22, 1942, describes a trailer mounted mixer having a single shaft screw auger mixer. Dry constituents are loaded into a hopper which discharges into the screw auger housing. The auger propels the dry mix towards the end of the housing, whereupon the mix drops through an opening formed in the floor into a discharge conduit. This discharge conduit has a first vertical leg, a second horizontal leg, and a final vertical leg. Water is metered by an adjustable valve, and the metered flow thereof is introduced into the discharge conduit at the elbow between the first vertical leg and the second horizontal leg. It should be noted that the screw auger functions purely as a conveyor, and no mechanical agitating apparatus is provided to blend the water and dry mix after these two materials have been fed into a common conduit or chamber.
None of the above inventions and patents, taken either singly or in combination, is seen to disclose the instant invention as claimed.